Taco SR501-HC-4 ZONE SWITCHING RELAY,1 ZONE,HI-CAPACITY,The single zone switching relay should be standard equipment for every installer. No matter what type of job, our single zone switching relay replaces every brand made by every manufacturer, and will even fit into the existing metal enclosure without rewiring incoming connections. The single zone switching relay is UL and CSA listed, uses a standard "ice cube" replaceable relay and is compatible with conventional and programmable thermostats. External indicator lights provide instant diagnostic feedback, making a snap of service calls or new installation start-ups
